添加生物炭对海南燥红壤N_(2)O和CO_(2)排放的影响

Effects of biochar addition on N_(2)O and CO_(2) emissions in Hainan dry red soil

为探讨海南燥红壤N_(2)O和CO_(2)排放对生物炭添加的响应,通过室内培养试验分析生物炭加入后对土壤化学性质、NH+4-N和NO-3-N含量以及N_(2)O和CO_(2)排放通量及累积排放量的影响。试验设置CK(不施生物炭)、B1(2%生物炭)、B2(4%生物炭)、B3(6%生物炭)4个处理。结果表明:添加生物炭后,土壤有机质、全氮和速效钾含量显著提高,较CK增幅分别为67.4%~246.6%、38.6%~90.9%和696.0%~1764.7%。相比于CK,不同量生物炭添加后均导致了NH+4-N和NO-3-N含量降低,总体上,不同处理NH+4-N浓度表现为CK>B3>B2>B1,NO-3-N含量表现为CK>B1>B2>B3;随培养时间增加,各处理NH+4-N浓度呈下降趋势,NO-3-N含量呈上升趋势。生物炭施用延后了N_(2)O排放通量出现峰值的时间。各处理之间N_(2)O和CO_(2)排放通量的变化过程大致表现出一致的趋势,即随培养时间延长,N_(2)O排放通量先升高后降低,CO_(2)排放通量先升高后趋于稳定。和CK相比,生物炭添加不同程度地促进了N_(2)O和CO_(2)排放,B1、B2和B3处理下N_(2)O累积排放量分别增加了399.2%、494.2%和194.5%,CO_(2)排放总量分别增加了87.6%、153.3%和147.6%。本研究结果显示,生物炭施用短期内促进了土壤N_(2)O和CO_(2)的排放通量。

To investigate the response of N_(2)O and CO_(2) emissions to biochar addition in dry red soil in Hainan,the effects of biochar addition on soil chemical properties,ammonium nitrogen and nitrate content,N_(2)O and CO_(2) emission fluxes,and cumulative emissions were analyzed through laboratory incubation experiments.Four treatments were set up:CK(no biochar),B1(2%biochar),B2(4%biochar),and B3(6%biochar).The results showed that the content of soil organic matter,total nitrogen,and available potassium increased significantly by 67.4%~246.6%,38.6%~90.9%,and 696.0%~1764.7%,respectively,compared with CK,and the content of NH+4-N and NO-3-N decreased after the addition of biochar.In general,the concentration of NH+4-N in the different treatments was CK>B3>B2>B1,and the content of NO-3-N was CK>B1>B2>B3.With the extension of incubation time,the concentration of NH+4-N in each treatment decreased,while the concentration of NO-3-N increased.Biochar application delayed the peak N_(2)O emission flux.Variations in N_(2)O and CO_(2) emission fluxes among different treatments showed a consistent trend;that was,with the extension of incubation time,N_(2)O and CO_(2) emission fluxes first increased and then decreased,and then increased again with the extension of incubation time.Compared with CK,the addition of biochar promoted N_(2)O and CO_(2) emissions to some degree,the cumulative N_(2)O emissions increased by 399.2%,494.2%,and 194.5%under treatments B1,B2,and B3,respectively,and the total CO_(2) emissions increased by 87.6%,153.3%,and 147.6%,respectively.The results show that biochar application increase N_(2)O and CO_(2) emissions in the short term.